Two of Britain's most beloved chocolate bars are set to get a healthy makeover with huge reductions in the amount of sugar they contain.

Low-sugar, high protein versions of the classic Mars and Snickers bars will be launched in High Street stores across the UK in January next year, to tackle concerns about obesity and health.

The normal full sugar bars are not being replaced but the healthier Mars 'More Protein' will contain 40 per cent less sugar than the original, while Snickers' version will have 30 per cent less sugar than the original.

Each bar will also contain 10g of protein.

Mars Wrigley Confectionery said the Mars will contain 17.5g of sugar per bar in total, with 14.1 sugar per bar in the Snickers.

Trade magazine The Grocer reported that the brand owner said the launch of the two new products will be followed later in 2019 by a new low-calorie range of single-serve bars.

They will all contain less than 100kcal - more than half that of the original bars in some cases.

The company said that the range which will include Mars, Snickers, Twix, Milky Way Crispy Rolls and Ripple bares.

They are intended to give consumers the opportunity to experience the great taste of their favourite brands in a smaller portion size.

The new bars mark the latest innovations since the appointment of UK general manager David Manzini in August last year.

New Skittles, Chewies, Starburst Minis and Maltese Truffles have all been launched in the past six months.

Mr Manzini said that tinkering with the recipes of 100-year-old brands when you want to 'keep the signature taste' is necessary to comply with 'the health and wellness agenda'.

He told The Grocer: 'It is a challenge the government and the country are facing and we need to support it. It is not a business opportunity but a business responsibility.

'We are really excited by what we call the portfolio of the future. There is an appetite for novelty, for innovation, new tastes and products, which is higher than in the past. There is a lot of talk about disruption in the market and I think we have a role to play in this by bringing in new brands and new disruption ourselves.'

Formulating products that comply with the growing 'health and wellness agenda' would be a key part, he added.

'I do believe we have a role and responsibility to play, which is why we are bringing out this proposition and why we are going to continue working on reformulation of our products by reducing the quantity of sugar. '